The attached spreadsheet needs to have the ".pdf" removed after it is downloaded.
The spreadsheet includes the loads and size calc for batteries, alternator and solar.

Two battery types were considered, after adjusting for effective capacity cycles and other aspects it appears that Firefly Oasis might be the better choice because it could be less expensive and more closely coincide with use of a boat off of a mooring. There is a little risk in the Firefly choice.

However we intend to mount enough Solar to charge the batteries from 80% SOC to 100% SOC in one day. (hopefully the batteries will cooperate and accept the energy offering at that rate)

With adequate solar for topping off both types of batteries, (far more important for the Flooded Deep Cycle batteries) it appears that we could use flooded deep cycle without PSOC (partial state of charge).

There are a couple of approaches,

1. Decide on Firefly, make a place for them and purchase them first (they are hard to get right now) and spend the money for solar a year later, but make sure these are topped off at the dock at least once a month.

2. Try to use our older Trojan T105 and make plans for new solar panels next year. Also we may have to get new Trojan Batteries next year too. Then later get Firefly Oasis.

3. Get a new smaller Alternator pulley in any case. Then upgrade the the Alternator and belt to serpentine.

With a genny, or decent alt setup and regular motoring and just a bit of solar,you should be able to get even a FLA bank to 100% full at least 2-3 times per week.

Thanks John, you advised that our batteries were probably PSOC all the time.

1. Last summer Engine Hrs were over 100 (more motoring than sailing) motored every day out of about 35.
2. Alt output was fine, indeed toward the end of the season, I noticed that sometimes on long runs (we had a lot of those) the voltage was higher than expected and it bothered me, but the season ended. This spring we found it was because sensors were not responding or were not located at the battery but on the alternator (although they worked in the previous position for many years). I keep an eye on this stuff.
3. Solar Panel on dodger top 14 watts, puts out about an amp.

This is why I thought my batteries should have been fine. It has worked well for many past years.

So the choices are?
1. Equalize and check batts. Get new batts if Load test does not work.
2. New pulley for anemic rebuilt 1995 Balmar alternator (but that does not really affect overall state of charging because we normally cruise at 2000-2500 rpm, just helps charging at anchor.
3. Larger solar. How large?

As you know, this spring I tried to reach 100 SOC with the engine - never again, its kind of stupid. 3 days of running the engine with an alternator/reg that is fine and putting out the required charge. That is certainly not going to happen again.

I intend to reconsider, redesign and rebuild the entire system eventually so that it works without a dock charge required. It's encouraging to hear it can be accomplished. If you have any other suggestions I'd love to hear them. Thanks. Rick

A 14W panel might keep up with self-discharge while in storage, certainly not to counted as part of the cycling inputs unless you are using other sources to get to 95+% in the morning and the bank is isolated.

So yes, if that's your upper limit for solar, and you're off grid for weeks, you need Firefly or LFP.

My recommendation for solar wattage is,

as much as you can fit, within your judgment of windage and aesthetics.

Looks like it is more than enough to charge the batteries up, plus as the batteries get closer to 100%SOC they will approx that "tailing 1 amp" that you mention.

If I were to leave the boat at the mooring at the end of the day with the batteries at 80%SOC = -44ah then the next day 250w PV (14.58amps) over 5hrs will go a long way towards fully charging the batteries. Then the next day they would be in float for sure.

Now if we were to be liveaboard, it would be a different matter, because systems are used all the time and there is not the same chance for recovery. In that case there is no doubt you would pile on as much PV as possible. To bad they can't make sails PV!

If these are good batteries (John says they are) and with prices like this why agonize about the condition of my Trojans? I'll just get new ones and be more careful going forward (provided the next dock based full charge & equalization does not help).

Please see the attached PDF (also the same spreadsheet with ".doc" added.)

I may need new batteries, but I also need to turn my battery box 90 degrees for proper orientation, so I am looking at the entire battery bank picture, before purchase. Currently with (2) GC2 and 225ah total, it is worthwhile considering how to double this amount.

I currently have an old Group 24 AGM located on the starboard side. I am considering removing this battery for a new (2)GC2 box.

I believe I could mount GC2 boxes, one in the port cockpit locker (current main bank) and one to starboard. I understand that it is best to have an entire bank together in one location, but there are certain physical constraints. The boat is a CCA design, and quite narrow towards the stern and the distance would be about 6' between the two boxes, with the engine between. This could almost be two separate banks, but I want to use them as one larger bank for obvious reasons.
- What problems would I have and how would I mitigate it?
- Shouldn't I make each box 2x6vdc=12vdc in series?
- The interconnect wiring will cross above the engine attached to the underside of the cockpit sole it would parallel from opposite ends.

I will also check to see if I can fit in the port locker, a new battery box 13.2"x16"x17.2 high" for (2)Trojan L16H-AC 11.7x7x16.75 6vdc 435ah. However those weigh 114 lbs and will be more difficult to move in and out of the locker. I don't have much hope for this one working.

Another more expensive alternative is something like a Trojan SCS225 Marine Dp Cycle 13.25"x6.75"x9.75" 12v 130ah 67lb $215 which allows deep cycling to 20%SOC, thus giving 60% x 260ah = 156ah bulk capacity (compared to the 56ah bulk capacity of 2-T105). Additionally it has 40% acceptance instead of 25%. I believe this battery would fit in my port locker in a new box. Each battery is also 67 lbs. I could keep my reserve battery in the starboard locker.

I also need to find room for new devices, such as an 120vac ECLI/GCI Main Breaker panel, galvanic isolator, Charger, ACR combiner, SmartGauge and Solar Controllers.

Where does the reserve battery get located? I could put it in the bow, or perhaps under the sink. Or perhaps have a portable 12Vdc with clips!

The calculated box has 1/2" clearances between batteries and case, the current batteries are quiet tight.
Is cooling air flow possibly an issue with the existing box? When charging with the balmar, the ARS-5 has a bat temp sensor and it seems to be ok, particularly when it is cool out (77f )

If located on the port side, the boat would list over, but I'd have much better access to the shaft without taking out the battery through the port locker.
It might be worthwhile trying to shift loads in the cabin to use this better configuration.
Also it might allow the Charger, ACR combiner and AC main panel to be mounted in the starboard locker.

There is better ventilation in the port locker, due to the starboard propane locker interfering with air flow. 12Both Switch is on the Port side. Moving the battery location will probably lengthen the runs from the alternator (port side of engine) and from batteries to 12Both.

Attached an image file and a pdf of of the diagrem. It represents the goals for the system, without having locations for all the panels figured out. Wire sizing and fuses may change, and may not be correct.

Review and measurement at the boat with this schematic and completion of a preliminary 120v AC Wiring Diagram is next.

Any observations and suggestions will be appreciated.
- Already found an error. The alternator (-) blk sensing wire should include the shunt and be wired on the load side away from the battery.

All manufacturers seem to want to attach their sensors directly to the battery terminals, which leads to a profusion of wires connected at the battery. This has been the situation since we had Loran and the solution to add a small Battery subpanel is not always good... So what absolutely needs to go on those terminals?

Well, there are some devices that do need direct battery power depending on if you want to be able to turn off the DC Panel when you leave the boat.
- Bilge pumps
- Anchor Light
- Some fancy anti-theft devices
- Charge sources like solar.

I think these can be reasonably put on a separate little panel right next to the batteries. However what about alternator sensors and temperature sensors (where the batteries could have 3 or more from regulator, solar controller, battery moniters)!

This leads me to the question of whether I should put the Balmar Regulator Black (-) direct to the Battery (-) in accord with the manufacturer's request, or on the load side of the shunt.

Quote:

Any observations and suggestions will be appreciated.
- Already found an error. The alternator (-) blk sensing wire should include the shunt and be wired on the load side away from the battery.

In addition to being the sense wire, this blk(-) is the ground for power to the Regulator. The regulator draws a very small load, something like 0.2amps. Therefore I am going to put it on the battery post, which will hopefully result in more accurate charging. However there will be a small loss in Battery Monitering, but the Link10 is not that accurate anyway.